This invention relates to a protective subceiling for damp rooms, such as industrial canteens, slaughter houses, laundries and the like, against rising steam vapors and the precipitation of particles contained therein, above which there is arranged at least one exhaust port. The lateral edges of arched ceiling elements are lodged in collecting channels for the precipitation and are spaced from the walls of the collecting channels, and the collecting channels are connected with a condensate absorber.
Such subceilings are known from German Pat. Nos. 1,609,427 and 2,414,573, and prevent the precipitation of steam vapors and albuminous and fatty substances on the actual or support ceilings above. The subceiling has a surface promoting the formation of condensate, as well as collecting channels for the condensate and drain pipes to carry it off. In order to remove any fat that may have deposited outside of the collecting channels without involving intensive cleaning labor, according to the German specification No. 2,414,573 the subceiling is provided with a liquid film by means of spraying elements, by which the precipitated particles can be removed. Even though this method basically causes a cleaning of the subceiling surfaces, very often fatty and albuminous substances will deposit and accumulate in the space between the collecting channel and the adjacent lateral edges of the ceiling elements, and thus the draining of the condensate or escape of vapor is not guaranteed.
On the other hand, by wetting with a liquid a considerable additional portion of waste water is produced. Further, in order to thoroughly clean the subceilings the spraying water must be heated to different temperatures. Below 50.degree. C. the albuminous substances are removed and above 50.degree. C. the fatty ones are removed.